{ ... }:
{
  text = ''
    # Convert between different formats.
    # By default tries to convert all files.
    # Usage: transcode <FORMAT> [FILES]
    function transcode() {
      local IFS=$'\n'
      local format=''${1}
      local targets=(''${@:2})
      [[ "''${targets}" = "" ]] && targets=($(_ls_file))

      # Report no format.
      if [[ "''${format}" = "" ]] || [[ "''${format}" =~ "." ]]; then
        _error "No format specified."
        help transcode
        return 2
      fi

      process() {
        # Define context names and status.
        local from="''${target##*.}"
        local to="''${format}"
        local output="''${target##*/}"
        output="''${output%.*}.''${to}"

        # Skip if file exists.
        [[ -f "''${output}" ]] && { _iterate_skip "Already exists."; return 0; }

        # Support multiple inputs.
        [[ "''${to}" = "mp3" ]] && from=""
        [[ "''${to}" = "flac" ]] && from=""
        [[ "''${to}" = "mka" ]] && from=""
        [[ "''${to}" = "mkv" ]] && from=""

        # Send convert.
        case "''${from}-''${to}" in
          "gz-xz"|"tgz-txz")
            _transcode_gz-xz "''${target}" "''${output}"
            ;;
          "xz-gz"|"txz-tgz")
            _transcode_xz-gz "''${target}" "''${output}"
            ;;
          "-mp3")
            _transcode_mp3 "''${target}" "''${output}"
            ;;
          "-flac")
            _transcode_flac "''${target}" "''${output}"
            ;;
          "-mka")
            _transcode_mka "''${target}" "''${output}"
            ;;
          "-mkv")
            _transcode_mkv "''${target}" "''${output}"
            ;;
          *)
            _error "Conversion ''${target##*.}-''${to} not supported."
            return 1
            ;;
        esac
      }

      _iterate_targets process ''${targets[@]}
    }

    function _transcode_gz-xz() {
      [[ -f "''${2}" ]] && return 1
      pv "''${1}" | gzip -d | xz -9e > "''${2}"
    }

    function _transcode_xz-gz() {
      [[ -f "''${2}" ]] && return 1
      pv "''${1}" | xz -d | gzip -1 > "''${2}"
    }

    function _transcode_mp3() {
      ffmpeg -n -i "''${1}" -c:a libmp3lame -b:a 320k -f mp3 "''${2}"
    }

    function _transcode_flac() {
      ffmpeg -n -i "''${1}" -c:a flac -f flac "''${2}"
    }

    function _transcode_mka() {
      local braudio=$(_ffprobe_ba "''${1}")
      [[ ''${braudio} -gt 128 ]] && braudio=128

      ffmpeg -n -i "''${1}" -ac 2 -c:a libopus -b:a ''${braudio}k -vn "''${2}"
    }

    function _transcode_mkv() {
      local keyint=$(_ffprobe_keyint "''${1}")
      local braudio=$(_ffprobe_ba "''${1}")
      local fps=$(_ffprobe_fps "''${1}")
      [[ ''${braudio} -gt 128 ]] && braudio=128
      [[ ''${fps} -gt 30 ]] && fps=30

      # ffmpeg -n -i "''${1}" -c:a libopus -b:a ''${braudio}k -c:v libsvtav1 -crf 30 -svtav1-params "fast-decode=1:tune=0" -preset 8 -pix_fmt yuv420p10le -g ''${keyint} -vf "scale=-2:min'(1080,ih)'" "''${2}"
      ffmpeg -n -i "''${1}" -map 0 -map -v -map V -map -t -dn -c:s srt -ac 2 -c:a libopus -b:a ''${braudio}k -c:v libsvtav1 -crf 30 -svtav1-params "tune=0" -pix_fmt yuv420p10le -g ''${keyint} -vf "scale=-2:min'(1080,ih)' , fps=''${fps}" "''${2}"
    }
  '';
}